$ python3 -m vmtest.vm -k '6.4.*' python3 -Bm drgn
...
>>> prog.stack_trace(1)
Traceback (most recent call last):
  File "/usr/lib64/python3.11/code.py", line 90, in runcode
    exec(code, self.locals)
  File "<console>", line 1, in <module>
Exception: unknown ORC entry type 3

This is because torvalds/linux@fb79944 changed the ORC entry format: the type is now 3 bits, and types now range from 0-4. torvalds/linux@ffb1b4a also previously changed the ORC format in a way that we didn't detect.

We might be able to guess the "version" of the format, but let's see if we can make upstream include a version identifier first.